ABSTRACT
Efficiency level, EL, was advanced in Chapter 1 as a theoretical construct that is an upgrade of the more common concept of reading achievement. Because the focal point of the causal model is efficiency level, EL, it is crucial that a strong case be made that this construct is an appropriate theoretical substitute for reading achievement. It should be acknowledged here at the outset of this chapter that the validity of the causal model presented in Chapter 1 can be tested by using traditional reading comprehension tests as measures of the EL construct.
